Sequential load switching utilizing discharge timing means



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Jan. 30, 1962 S. SEQUENTIAL C. ROCKAFELLOW LOAD SWITCHING UTILIZINGDISCHARGE TIMING MEANS Filed sept. 2, 195e INVENTOR. SMART C /'a Mara owHTTRNE YS' United States This invention relates to electrical timingequipment and it relates particularly to circuitry for simultaneouslystarting a plurality of independently operable timers, each thereofbeing connected to an independently operable load actuating device.

There are numerous instances in the designing of various types ofelectrical equipment where it is desirable to utilize a plurality ofindependently operable timers which are each connected to a valve andload circuit and which are connected with respect to each other in sucha manner that the timers will operate in a definite relationship to eachother. One way in which an accurately controllable relationship may beestablished between said timers is to effect a simultaneous starting ofthe timing function of each thereof. Prior attempts to provide circuitryof this nature, insofar as I am aware, have resulted in undesirablycomplicated circuits or circuits whose functioning was not entirelyaccurate.

Accordingly, the objects of the invention include the following:

(l) To provide a circuit for simultaneously starting a plurality ofindependently operable timers, each of said timers being respectivelyconnected to an independent valve and load circuit.

(2) To provide a circuit, as aforesaid, of relatively simpleconstruction having both low initial construction cost and lowmaintenance cost.

(3) To provide a circuit, as aforesaid, whose operation is initiated bythe actuation of only a single control element and wherein each timer isfree from interference by any of the other associated timers.

(4) To provide a circuit, as aforesaid, which can be readily adapted forhandling differing numbers of tim- "ing circuits and their respectivelyassociated valve and load circuits.

(5) To provide a circuit, as aforesaid, which will be capable ofoperating with a high degree of accuracy.

(6) To provide a circuit, as aforesaid, which will initiate a pluralityof timing functions upon a change in the conductive condition of asingle electric discharge device.

Other objects and purposes of the invention will become apparent topersons acquainted with apparatus of this general type upon reading thefollowing disclosure and inspection of the accompanying drawing which isa schematic diagram of a circuit embodying the invention.

In general, the invention provides a plurality of parallel connected,independent, time-constant circuits con nected in the anode circuit of asuitable electric discharge device, such as a thyratron. A rectifier isconnected between each time constant circuit and the anode of saidelectric discharge device. The negative side of the capacitor in eachtime-constant circuit is connected for controlling the conductivity of asuitable potential responsive electric valve, such as by being connectedto the grid of a thyratron, for controlling actuation of the respectiveloads.

YTurning now to a more detailed consideration of the circuitillustrating and embodying the invention, there is shown a pair of busconductors 1 and 2 which are connected to any suitable source ofalternating potential, said source in this case being the secondarywinding 3 3,l 9,33 latented Jan. 30, 1962 ice of a transformer 4 whoseprimary winding 6 is energized by a suitable A.C. source.

A suitable electric valve 7 is connected between the bus conductors 1and 2. The valve 7 is here shown as being a single thyratron tube, butit could also be an entire electronic circuit or any other suitable formof electric valving apparatus. The cathode of the valve 7 is connectedby a conductor 8 to the bus conductor 2. The grid of the valve 7 isconnected through a resistance 9 to said bus conductor 2 and is alsoconnected through a switch 11 and a battery 12 to the bus conductor 2,the negative side of said battery being connected to said grid. it willbe recognized that the switch 11 may also be either a singleinstrumentality, such as the manually operable switch shown in thedrawing, or it may be an entire switching circuit.

The anode of the valve 7 is connected to one side of a plurality ofparallel connected, time constant circuits 13, 14, 15 and 16 and theother sides of said circuits are connected to the bus conductor 1. Allof the time-constant circuits are substantially the same and hence adetailed description of only circuit 13 will be given, the descriptionapplying equally to the other circuits. The corresponding parts of theother circuits 14, 15 and 16 are indicated by the same numerals asutilized for circuit 13 with the suffixes a, b, and c, respectively,added thereto.

The circuit 13 comprises a conventional time-constant circuit consistingof a capacitor 17 connected in parallel with a resistor 18, one of saidelements, here the resistor 18, being variable for time adjustmentpurposes. The parallel connected capacitor 17 and resistor 18 areconnected to a junction point 31 and thence serially connected through arectifier 19 to the anode of the valve 7. The rectifier 19 is sensed topermit current flow from bus conductor 1 to bus conductor 2 so that theside of the capacitor 17 adjacent thereto is negative.

A plurality of loads 21, 22, 23 and 24 are respectively connected inseries to suitable valves 26, 27, 28 and 29. Each load and its valve,sometimes herein referred to as a load-and-valve circuit, are connectedto any suitable source of power, which sources may be the same `ordifferent from each other provided only that the cathodes of each of thevalves 26, 27, 28 and 29 are connected to the positive sides of therespectively related capacitors, said last-named source being here shownas the bus conductors 1 and 2. The junction point 31 located between thenegative side of capacitor 17 and the rectifier 19 is connected by theconductor 32 to the grid of the valve 26. Corresponding junction points31a, 31h, and 31e are similarly connected by conductors 33, 3dand 35 tothe grids of the valves 27, 28 and 29, respectively.

Suitable filament connections for the valves are made in a conventionalmanner but are not shown herein for the sake of simplifying theillustration.

Operation The operation of this apparatus will be readily understood butwill be briefly summarized for purposes of completeness.

With the tube 7 normally conductive, potential will be conducted throughthe rectifiers 19, 19a, 19]), and 19C in one direction to charge thecapacitors 17, 17a, 1711 and 17e. Thus, a negative potential is normallyapplied to each of the valves 26, 27, 28 and 29, respectively, to holdsaid valves blocked. The several variable resistors 1S, 18a, 18b, and18C may be set in a conventional manner to obtain the desired rate ofdischarge of the charge on the capacitor connected thereto.

Upon closure of the switch 11, the negative bias from the battery 12 isapplied to the control electrode of the :nordsee tube 7 thereby blockingsaid tube and terminating the charging of the several capacitors. Thisinitiates simultaneous commencement of discharge of the capacitorsthrough their respectively connected variable resistances at ratesdetermined by the setting of the variable resistances. When thecapacitors have discharged to a point such that the potential appearingat the points 31, 31a, 31h, and 31C, respectively, reach certainpredetermined levels, corresponding potentials appearing on the controlelectrodes of the several valves 26, 27, 28 and 29, respectively, willthereby permit said valves to conduct, which conduction occurs atpreselected periods of time following the closure of the switch 11 andwhich periods of time are determined by the settings of the variableresistors. The rectitiers 19, 19a, 19h and 19C preve-nt the charge onany given capacitor from affecting the potential at any of said points31, 31a, 31b and 31C other than the point directly connected to saidgiven capacitor.

While a particular preferred embodiment of the invention has beendescribed above, the invention includes such modifications or changestherein as lie within the scope of the appended claims.

What is claimed is:

1. In a circuit for independently aitecting the conductivity of aplurality of load-actuating electric valves, each said valve including apotential responsive control means, the combination comprising: aplurality of timeconstant circuits, each circuit including a chargeableelcment and a discharging device; an electric valve having an anode, acathode and a control electrode; circuitry connecting one end of each ofthe time-constant circuits to a source of alternating potential; aplurality of one-way conductive means, therebeing one of each of saidone-way conductive means connected in series with. each time-constantcircuit and circuitry connecting the other end of each of saidtime-constant circuits, respectively, through one of said one-wayconductive means tothe anode of said electric valve, said one-wayconductive means each being sensed to permit the conduction of potentialfrom one side of said source through its associated chargeable elementto said electric valve; means connecting the cathode of said electricvalve to the other side ot' said source; means controlling theconductivity of said valve; a plurality of load-actuating electricvalves, each of said last-named valves having a potential-responsivecontrol means and a source of potential connected to each of saidlast-named valves so that same actuate a load when they are conductive;separate circuits connecting a point located between each of saidone-way conductive means and the negative side of the chargeable elementassociated therewith to said control means for one of saidload-actuating electric valves so that said load-actuating electricvalves may be rendered conductive in sequence.

2. In a circuit for independently affecting the conductivity of aplurality of electric load-actuating valves, each said valve including apotential responsive control means, the combination comprising: aplurality of timeconstant circuits, each circuit including a capacitorand a resistor connected in parallel; an electric control valve havingan anode, a cathode and a control electrode; circuitry connecting eachof the time-constant circuits at one end thereof to a source ofalternating potential; a plurality of continuously one-way conductiverectiers, one of said rectirlers being connected in series with eachtime-constant circuit and circuitry connecting the other end of each ofsaid time-constant circuits, respectively, through one of saidrectifiers to the anode of said electric control valve, said rectiiierseach being sensed to permit the conduction of potential from said oneside of said source through said rectitiers to said electric controlvalve; means connecting the cathode of said electric control valve tothe other side of said source; means controlling the conductivity ofsaid control valve; a plurality of load-actuating electric valves eachof said last-named valves having a potential-responsive controlelectrode and a source of potential connected to each of said lastnamedvalve means so that same actuate a load when they are conductive;separate circuits connecting a point located between each rectitier andthe negative side of the capacitor associated therewith to said controlmeans for one of said load-actuating electric valves so that saidload-actuating electric valves may be rendered conductive :in sequence.

3. The apparatus defined in claim 2 wherein the resistances of thetime-constant circuits are variable.

4. A circuit for actuating a plurality of loads in timed relation toeach other, comprising: a source of alternating potential; a pluralityof parallel connected, time-constant circuits comprising an adjustableresistance and a capacitance in parallel, each circuit being connectedat one end thereof to one side of said source; a continuously onewayconductive rectifier in series with each of said timeconstant circuitsand connected to the other end thereof, said rectiiiers being sensed topermit current flow from said one end of each of said time-constantcircuits to the other end thereof; means connecting said rectiiers to acommon point; a normally conductive thyratron having an anode, a cathodeand a controlelectrode; means connecting said anode to said common pointand means connecting said cathode to the other side of said source; asource of substantially constant potential; a switch and meansconnecting the negative terminal of said constant potential sourcethrough said switch to said control electrode whereby said thyratron maybe rendered non-conductive upon closing of said switch; a plurality ofnormally non-conductive load thyratrons, each load thyratron having ananode, a cathode and a control electrode; a source of potentialconnected to said load thyratrons; a load connected to the anode of eachload thyratron; means connecting a point between the other end o' eachtimeconstant circuit and its associated rectifier to the controlelectrode of one of said load thyr'atrons whereby said load thyratronsare, respectively, rendered conductive a predetermined time afterclosing of said switch.

5. A circuit for actuating a plurality of loads in timed relation toeach other; a plurality of loads; a controllably conductive deviceassociated with each load for controlling actuation thereof and meansfor supplying potential to said device; a plurality of parallelconnected timing circuits, each circuit being associated with one ofsaid devices for controlling the conductivity thereof, each circuitincluding a capacitor; a source of alternating potential and meansconnecting said source to said timing circuits for charging thecapacitors thereof; a plurality of continuously one-way conductivemeans, each thereof being connected in series with one of said timingcircuits for isolating the charge of the capacitor of said timingcircuit from the other timing circuits; a single, controllable, normallyconductive electric valve in series with all of said timing circuits andconnected between the respective sides of said source; a switch; asourceof negative potential connected through said switch to saidnormally conductive electric valve for rendering said valvenon-conductive after closing of said switch whereby said loads will beactuated at timed intervals after closing of said switch.

References Cited in the tile of this patent UNITED STATES PATENTS2,577,499 Anderson Dec. 4, 1951 2,677,052 Rockafellow Apr. 27, 19542,710,326 Collom .Tune 7, 1955 2,721,265 Rothman et al Oct. 18, 19552,831,108 Barditch Apr. l5, 1958 2,906,870 Huntley et al Sept. 29, 1959

